Add Real Enable/Disable Flags for Cross-Module Incremental Builds

include/swift/Frontend/FrontendOptions.h

@@ -298,7 +298,7 @@ class FrontendOptions {
   ///
   /// This flag is currently only propagated from the driver to
   /// any merge-modules jobs.
-  bool EnableExperimentalCrossModuleIncrementalBuild = false;
+  bool DisableCrossModuleIncrementalBuild = false;
 
   /// Best effort to output a .swiftmodule regardless of any compilation
   /// errors. SIL generation and serialization is skipped entirely when there

include/swift/Option/Options.td

@@ -1111,6 +1111,18 @@ def emit_supported_features : Flag<["-"], "emit-supported-features">,
   HelpText<"Emit a JSON file including all supported compiler features">, ModeOpt,
   Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
 
+def enable_incremental_imports :
+  Flag<["-"], "enable-incremental-imports">,
+  Flags<[FrontendOption]>,
+  HelpText<"Enable cross-module incremental build metadata and "
+           "driver scheduling for Swift modules">;
+
+def disable_incremental_imports :
+  Flag<["-"], "disable-incremental-imports">,
+  Flags<[FrontendOption]>,
+  HelpText<"Disable cross-module incremental build metadata and "
+           "driver scheduling for Swift modules">;
+
 def index_file : Flag<["-"], "index-file">,
   HelpText<"Produce index data for a source file">, ModeOpt,
   Flags<[NoInteractiveOption, DoesNotAffectIncrementalBuild]>;

include/swift/Serialization/SerializationOptions.h

@@ -132,7 +132,7 @@ namespace swift {
     bool SerializeAllSIL = false;
     bool SerializeOptionsForDebugging = false;
     bool IsSIB = false;
-    bool ExperimentalCrossModuleIncrementalInfo = false;
+    bool DisableCrossModuleIncrementalInfo = false;
   };
 
 } // end namespace swift

lib/Driver/Driver.cpp

@@ -1008,8 +1008,9 @@ Driver::buildCompilation(const ToolChain &TC,
     const bool EmitFineGrainedDependencyDotFileAfterEveryImport = ArgList->hasArg(
         options::
             OPT_driver_emit_fine_grained_dependency_dot_file_after_every_import);
-    const bool EnableCrossModuleDependencies = ArgList->hasArg(
-        options::OPT_enable_experimental_cross_module_incremental_build);
+    const bool EnableCrossModuleDependencies
+        = ArgList->hasArg(options::OPT_enable_incremental_imports,
+                          options::OPT_disable_incremental_imports, true);
 
     // clang-format off
     C = std::make_unique<Compilation>(

lib/Driver/ToolChains.cpp

@@ -1050,9 +1050,7 @@ ToolChain::constructInvocation(const MergeModuleJobAction &job,
 
   context.Args.AddLastArg(Arguments, options::OPT_import_objc_header);
 
-  context.Args.AddLastArg(
-      Arguments,
-      options::OPT_enable_experimental_cross_module_incremental_build);
+  context.Args.AddLastArg(Arguments, options::OPT_disable_incremental_imports);
 
   Arguments.push_back("-module-name");
   Arguments.push_back(context.Args.MakeArgString(context.OI.ModuleName));

lib/Frontend/ArgsToFrontendOptionsConverter.cpp

@@ -103,8 +103,8 @@ bool ArgsToFrontendOptionsConverter::convert(
 
   Opts.ImportPrescan |= Args.hasArg(OPT_import_prescan);
 
-  Opts.EnableExperimentalCrossModuleIncrementalBuild |=
-      Args.hasArg(OPT_enable_experimental_cross_module_incremental_build);
+  Opts.DisableCrossModuleIncrementalBuild |=
+      Args.hasArg(OPT_disable_incremental_imports);
 
   // Always track system dependencies when scanning dependencies.
   if (const Arg *ModeArg = Args.getLastArg(OPT_modes_Group)) {

lib/Frontend/Frontend.cpp

@@ -178,8 +178,8 @@ SerializationOptions CompilerInvocation::computeSerializationOptions(
       opts.SerializeOptionsForDebugging.getValueOr(
           !isModuleExternallyConsumed(module));
 
-  serializationOpts.ExperimentalCrossModuleIncrementalInfo =
-      opts.EnableExperimentalCrossModuleIncrementalBuild;
+  serializationOpts.DisableCrossModuleIncrementalInfo =
+      opts.DisableCrossModuleIncrementalBuild;
 
   return serializationOpts;
 }

lib/Frontend/ModuleInterfaceBuilder.cpp

@@ -79,10 +79,13 @@ bool ModuleInterfaceBuilder::collectDepsForSerialization(
   path::native(ResourcePath);
 
   auto DTDeps = SubInstance.getDependencyTracker()->getDependencies();
-  SmallVector<StringRef, 16> InitialDepNames(DTDeps.begin(), DTDeps.end());
-  InitialDepNames.push_back(interfacePath);
-  InitialDepNames.insert(InitialDepNames.end(),
-                         extraDependencies.begin(), extraDependencies.end());
+  SmallVector<std::string, 16> InitialDepNames(DTDeps.begin(), DTDeps.end());
+  auto IncDeps = SubInstance.getDependencyTracker()->getIncrementalDependencyPaths();
+  InitialDepNames.append(IncDeps.begin(), IncDeps.end());
+  InitialDepNames.push_back(interfacePath.str());
+  for (const auto &extra : extraDependencies) {
+    InitialDepNames.push_back(extra.str());
+  }
   SmallString<128> Scratch;
 
   for (const auto &InitialDepName : InitialDepNames) {

lib/FrontendTool/FrontendTool.cpp

@@ -1536,7 +1536,11 @@ static bool performCompileStepsPostSILGen(CompilerInstance &Instance,
 
     SerializationOptions serializationOpts =
         Invocation.computeSerializationOptions(outs, Instance.getMainModule());
-    if (serializationOpts.ExperimentalCrossModuleIncrementalInfo) {
+
+    const bool canEmitIncrementalInfoIntoModule =
+        !serializationOpts.DisableCrossModuleIncrementalInfo &&
+        (Action == FrontendOptions::ActionType::MergeModules);
+    if (canEmitIncrementalInfoIntoModule) {
       const auto alsoEmitDotFile =
           Instance.getInvocation()
               .getLangOptions()

lib/FrontendTool/LoadedModuleTrace.cpp

@@ -577,7 +577,11 @@ static void computeSwiftModuleTraceInfo(
     path::replace_extension(modPath, swiftInterfaceExt);
   };
 
-  for (auto &depPath : depTracker.getDependencies()) {
+  auto deps = depTracker.getDependencies();
+  SmallVector<std::string, 16> dependencies{deps.begin(), deps.end()};
+  auto incrDeps = depTracker.getIncrementalDependencyPaths();
+  dependencies.append(incrDeps.begin(), incrDeps.end());
+  for (const auto &depPath : dependencies) {
 
     // Decide if this is a swiftmodule based on the extension of the raw
     // dependency path, as the true file may have a different one.

lib/Serialization/Serialization.cpp

@@ -5482,7 +5482,7 @@ void Serializer::writeToStream(
     S.writeInputBlock(options);
     S.writeSIL(SILMod, options.SerializeAllSIL);
     S.writeAST(DC);
-    if (options.ExperimentalCrossModuleIncrementalInfo && DepGraph) {
+    if (!options.DisableCrossModuleIncrementalInfo && DepGraph) {
       fine_grained_dependencies::writeFineGrainedDependencyGraph(
           S.Out, *DepGraph, fine_grained_dependencies::Purpose::ForSwiftModule);
     }

test/Driver/cross_module.swift

@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t/sub)
 // RUN: echo "{\"\": {\"swift-dependencies\": \"cross_module.swiftdeps\"}}" > %t/ofm.json
-// RUN: %swiftc_driver -incremental -emit-module -module-name cross_module -output-file-map=%/t/ofm.json -driver-print-jobs -target x86_64-apple-macosx10.9 %s -enable-experimental-cross-module-incremental-build 2>^1 | %FileCheck -check-prefix ENABLE %s
+// RUN: %swiftc_driver -incremental -emit-module -module-name cross_module -output-file-map=%/t/ofm.json -driver-print-jobs -target x86_64-apple-macosx10.9 %s -disable-incremental-imports 2>^1 | %FileCheck -check-prefix ENABLE %s
 
 // ENABLE: {{bin(/|\\\\)swift(-frontend|c)?(\.exe)?"?}} -frontend -merge-modules
-// ENABLE-SAME: -enable-experimental-cross-module-incremental-build
+// ENABLE-SAME: -disable-incremental-imports

test/Incremental/CrossModule/external-cascade.swift

@@ -18,9 +18,9 @@
 // Set up a clean incremental build of all three modules
 //
 
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -enable-experimental-cross-module-incremental-build -module-name C -I %t -output-file-map %t/C.json -working-directory %t -import-objc-header %t/bridging-header.h -Xfrontend -validate-tbd-against-ir=none -driver-show-incremental -driver-show-job-lifecycle C.swift
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -enable-experimental-cross-module-incremental-build -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -enable-experimental-cross-module-incremental-build -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -module-name C -I %t -output-file-map %t/C.json -working-directory %t -import-objc-header %t/bridging-header.h -Xfrontend -validate-tbd-against-ir=none -driver-show-incremental -driver-show-job-lifecycle C.swift
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift
 
 //
 // Now change a header and ensure that the rebuild cascades outwards
@@ -29,10 +29,10 @@
 // RUN: rm %t/another-header.h
 // RUN: cp %S/Inputs/external-cascade/another-header.h %t/another-header.h
 // RUN: touch %t/another-header.h
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -enable-experimental-cross-module-incremental-build -module-name C -I %t -output-file-map %t/C.json -working-directory %t -import-objc-header %t/bridging-header.h -Xfrontend -validate-tbd-against-ir=none -driver-show-incremental -driver-show-job-lifecycle C.swift 2>&1 | %FileCheck -check-prefix MODULE-C %s
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -enable-experimental-cross-module-incremental-build -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift 2>&1 | %FileCheck -check-prefix MODULE-B %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -module-name C -I %t -output-file-map %t/C.json -working-directory %t -import-objc-header %t/bridging-header.h -Xfrontend -validate-tbd-against-ir=none -driver-show-incremental -driver-show-job-lifecycle C.swift 2>&1 | %FileCheck -check-prefix MODULE-C %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift 2>&1 | %FileCheck -check-prefix MODULE-B %s
 // RUN: touch %t/B.swiftmodule
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -enable-experimental-cross-module-incremental-build -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift 2>&1 | %FileCheck -check-prefix MODULE-A %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift 2>&1 | %FileCheck -check-prefix MODULE-A %s
 
 // MODULE-C: Job finished: {generate-pch: bridging-header-[[BRIDGING_HEADER:.*]].pch <= bridging-header.h}
 // MODULE-C: Job finished: {compile: C.o <= C.swift bridging-header-[[BRIDGING_HEADER]].pch}
@@ -51,9 +51,9 @@
 // And ensure that the null build really is null.
 //
 
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -enable-experimental-cross-module-incremental-build -module-name C -I %t -output-file-map %t/C.json -working-directory %t -import-objc-header %t/bridging-header.h -Xfrontend -validate-tbd-against-ir=none -driver-show-incremental -driver-show-job-lifecycle C.swift 2>&1 | %FileCheck -check-prefix MODULE-C-NULL %s
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -enable-experimental-cross-module-incremental-build -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift 2>&1 | %FileCheck -check-prefix MODULE-B-NULL %s
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -enable-experimental-cross-module-incremental-build -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift 2>&1 | %FileCheck -check-prefix MODULE-A-NULL %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -module-name C -I %t -output-file-map %t/C.json -working-directory %t -import-objc-header %t/bridging-header.h -Xfrontend -validate-tbd-against-ir=none -driver-show-incremental -driver-show-job-lifecycle C.swift 2>&1 | %FileCheck -check-prefix MODULE-C-NULL %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift 2>&1 | %FileCheck -check-prefix MODULE-B-NULL %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift 2>&1 | %FileCheck -check-prefix MODULE-A-NULL %s
 
 // MODULE-C-NULL: Job finished: {generate-pch: bridging-header-[[BRIDGING_HEADER:.*]].pch <= bridging-header.h}
 // MODULE-C-NULL: Job skipped: {compile: C.o <= C.swift bridging-header-[[BRIDGING_HEADER]].pch}

test/Incremental/CrossModule/linear.swift

@@ -18,18 +18,18 @@
 // Set up a clean incremental build of all three modules
 //
 
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -enable-experimental-cross-module-incremental-build -module-name C -I %t -output-file-map %t/C.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle -DOLD C.swift
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -enable-experimental-cross-module-incremental-build -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -enable-experimental-cross-module-incremental-build -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -module-name C -I %t -output-file-map %t/C.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle -DOLD C.swift
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift
 
 //
 // Now change C and ensure that B rebuilds but A does not
 //
 
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -enable-experimental-cross-module-incremental-build -module-name C -I %t -output-file-map %t/C.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle -DNEW C.swift 2>&1 | %FileCheck -check-prefix MODULE-C %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -module-name C -I %t -output-file-map %t/C.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle -DNEW C.swift 2>&1 | %FileCheck -check-prefix MODULE-C %s
 // RUN: touch %t/C.swiftmodule
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -enable-experimental-cross-module-incremental-build -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift 2>&1 | %FileCheck -check-prefix MODULE-B %s
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -enable-experimental-cross-module-incremental-build -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift 2>&1 | %FileCheck -check-prefix MODULE-A %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift 2>&1 | %FileCheck -check-prefix MODULE-B %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift 2>&1 | %FileCheck -check-prefix MODULE-A %s
 
 // MODULE-C: Incremental compilation has been disabled
 
@@ -44,9 +44,9 @@
 // And ensure that the null build really is null.
 //
 
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -enable-experimental-cross-module-incremental-build -module-name C -I %t -output-file-map %t/C.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle -DNEW C.swift 2>&1 | %FileCheck -check-prefix MODULE-C-NULL %s
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -enable-experimental-cross-module-incremental-build -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift 2>&1 | %FileCheck -check-prefix MODULE-B-NULL %s
-// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -enable-experimental-cross-module-incremental-build -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift 2>&1 | %FileCheck -check-prefix MODULE-A-NULL %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/C.swiftmodule -module-name C -I %t -output-file-map %t/C.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle -DNEW C.swift 2>&1 | %FileCheck -check-prefix MODULE-C-NULL %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/B.swiftmodule -module-name B -I %t -output-file-map %t/B.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle B.swift 2>&1 | %FileCheck -check-prefix MODULE-B-NULL %s
+// RUN: cd %t && %target-swiftc_driver -c -incremental -emit-dependencies -emit-module -emit-module-path %t/A.swiftmodule -module-name A -I %t -output-file-map %t/A.json -working-directory %t -driver-show-incremental -driver-show-job-lifecycle A.swift 2>&1 | %FileCheck -check-prefix MODULE-A-NULL %s
 
 // MODULE-C-NULL: Job skipped: {compile: C.o <= C.swift}
 // MODULE-C-NULL: Job skipped: {merge-module: C.swiftmodule <= C.o}